colon `::`?

What is this double-colon :: ? Eg Foo::Bar . I found a definition: The :: is a unary operator that allows: constants, instance methods and class methods defined within a class or module, to be accessed from anywhere outside the class or module. What good is scope (private, protected) if you can just use :: to expose anything? :: is basically a namespace resolution operator. It allows yo

冒号`::`?

什么是这个双冒号:: ? 例如Foo::Bar 。 我找到了一个定义: The ::是一个一元运算符,它允许:在类或模块内定义的常量,实例方法和类方法可以从类或模块外的任何地方访问。 如果你可以使用::来暴露任何东西,范围(私有,受保护)有什么好处? ::基本上是一个名称空间解析运算符。 它允许您访问模块中的项目或课堂中的课程级别项目。 例如,假设你有这样的设置: module SomeModule module InnerModule

What's the difference between equal?, eql?, ===, and ==?

I am trying to understand the difference between these four methods. I know by default that == calls the method equal? which returns true when both operands refer to exactly the same object. === by default also calls == which calls equal? ... okay, so if all these three methods are not overridden, then I guess === , == and equal? do exactly the same thing? Now comes eql? . What does thi

平等?,eql ?, ===和==有什么区别?

我想了解这四种方法之间的区别。 我知道默认==调用方法equal? 当两个操作数引用完全相同的对象时,它将返回true。 ===默认情况下也调用equal?调用== equal? ...好吧,如果所有这三种方法都没有被覆盖,那么我猜=== , ==和equal? 做同样的事情? 现在来eql? 。 这是做什么的(默认情况下)? 它是否调用操作数的哈希/ ID? 为什么Ruby有这么多的平等标志? 他们是否应该在语义上有所不同? 我将在这里大量引用Ob

What does map(&:name) mean in Ruby?

I found this code in a RailsCast: def tag_names @tag_names || tags.map(&:name).join(' ') end What does the (&:name) in map(&:name) mean? It's shorthand for tags.map(&:name.to_proc).join(' ') If foo is an object with a to_proc method, then you can pass it to a method as &foo , which will call foo.to_proc and use that as the method's block. The Symbol#t

在Ruby中map(&:name)是什么意思?

我在RailsCast中找到了这段代码: def tag_names @tag_names || tags.map(&:name).join(' ') end 什么是(&:name)在map(&:name)是什么意思? 它是tags.map(&:name.to_proc).join(' ')的缩写 如果foo是一个带有to_proc方法的对象,那么可以将它作为&foo传递给一个方法,该方法将调用foo.to_proc并将其用作方法的块。 Symbol#to_proc方法最初由ActiveSupport添加,但已被集成到Ruby 1.8.7中

Run a Ruby library from the command

I've just learned the basics of Ruby after being very happy with Python for several years (I'm still using Python for some things), but I'd like to know if there's an idiom or hack to solve this particular problem. I have a Ruby script which I'd like to be able to do require script_name with, but I'd also like to be able to run ruby script_name.rb from the terminal and h

从命令运行一个Ruby库

我刚刚学习了几年Ruby对Python的满意之后(我仍然在使用Python做某些事情),但是我想知道是否有成语或破解来解决这个特定问题。 我有一个Ruby脚本,我希望能够做到这一点,它require script_name ,但我也希望能够从终端运行ruby script_name.rb并让它作为命令行脚本运行。 在Python中,这可以通过在脚本底部具有以下结构来完成: if __name__ == '__main__': # do something here 但是,我似乎无法在Ruby中找到等价物

undefined method `visitor' for Rails 3 db:migrate

I am experiencing an exception while doing a database migration in Rails 3. undefined method `visitor' for #<ActiveRecord::ConnectionAdapters::Mysql2Adapter:0x00000103dea3d8> Edit Please check the solution here. No occurrence for the string visitor inside my project so I am puzzled. Here is the full dump: $ rake db:migrate --trace ** Invoke db:migrate (first_time) ** Invoke environ

未定义的方法`访客'的Rails 3分贝:迁移

在Rails 3中进行数据库迁移时,我遇到了异常。 undefined method `visitor' for #<ActiveRecord::ConnectionAdapters::Mysql2Adapter:0x00000103dea3d8> 编辑 请在这里查看解决方案。 我的项目中没有出现字符串visitor所以我感到困惑。 这是完整的转储: $ rake db:migrate --trace ** Invoke db:migrate (first_time) ** Invoke environment (first_time) ** Execute environment ** Invoke db:load_config (firs

Why do both ways of accesing module functions exist in Ruby?

module A def self.func puts "func" end end >> A.func func >> A::func func Why do both . and :: exist? Why not only . ? The scope resolution operator ( :: ) can resolve constants, instance methods, and class methods, so we can use that operator for essentially any method as long as we are looking in the right place. Additionally, since the method "func" is def

为什么在Ruby中存在两种访问模块函数的方法?

module A def self.func puts "func" end end >> A.func func >> A::func func 为什么这两个. 和::存在? 为什么不只是. ? 范围解析运算符( ::可以解析常量,实例方法和类方法,因此,只要我们在正确的位置查找,我们就可以基本上使用该运算符。 此外,由于方法“func”被定义为模块A的类方法(通过self.func ,类似于“静态”方法),它直接属于模块(它本身就是一个对象),因此可以用模块作为接收

Compact gem or libraries for improving Ruby skills?

I'm an advanced beginner/intermediate Ruby programmer. I'm really working on improving my Ruby skills, with specific focus on writing more efficient, compact, idiomatic Ruby, following solid testing practices, and learning and adhering to project structure and other general best practices. With that in mind, I've been looking for good material to learn from. I've checked out a

用于提高Ruby技能的紧凑型宝石或库?

我是一名高级的初级/中级Ruby程序员。 我真的在努力提高自己的Ruby技能,特别关注编写更高效,紧凑,惯用的Ruby,遵循可靠的测试实践,学习并遵守项目结构和其他一般最佳实践。 考虑到这一点,我一直在寻找好的材料来学习。 我已经检查了几个Play Play Peepcode屏幕视频,这很棒,但不是我正在寻找的。 我探讨了Github,但大多数我熟悉的项目可能会非常庞大​​ - 我花费了太多时间来解开事情的实际融合,试图构建一个事物的

Cucumber statistics gem not working

I am using Cucumber Capybara with Ruby for automation. I have install the cucumber statistics gem for reporting purpose. I have added require 'cucumber_statistics/autoload' in env.rb file. After successful execution of feature file it is showing error as : undefined method regexp_source' for #<Cucumber::Glue::StepDefinition:0x0000000293dda0> (NoMethodError) /usr/local/rvm/g

黄瓜统计宝石不起作用

我正在使用Cucumber和Cucumber来进行自动化。 我已安装黄瓜统计宝石用于报告目的。 我在env.rb文件中添加了require'cucumber_statistics / autoload'。 成功执行特征文件后,它显示错误为: 未定义的方法regexp_source' for #<Cucumber::Glue::StepDefinition:0x0000000293dda0> (NoMethodError) /usr/local/rvm/gems/ruby-2.2.2/gems/cucumber_statistics-2.3.0/lib/cucumber_statistics/formatter.rb:2

`sysread': end of file reached (EOFError)

require 'net/http' require 'uri' Net::HTTP.get_print URI.parse('https://forums.malwarebytes.org/index.php?showtopic=49893') 我得到一个错误,如下所示:: c:/ruby/lib/ruby/1.8/net/protocol.rb:133:在sysread': end of file reached (EOFError) from c:/ruby/lib/ruby/1.8/net/protocol.rb:133:in rbuf_fill'from c:/ruby/lib/ruby/1.8/timeout.rb:56:in timeout' from c:/ruby/lib/ruby/1.8/timeout.rb

`sysread':到达文件结尾(EOFError)

require 'net/http' require 'uri' Net::HTTP.get_print URI.parse('https://forums.malwarebytes.org/index.php?showtopic=49893') 我得到一个错误,如下所示:: c:/ruby/lib/ruby/1.8/net/protocol.rb:133:在sysread': end of file reached (EOFError) from c:/ruby/lib/ruby/1.8/net/protocol.rb:133:in rbuf_fill'from c:/ruby/lib/ruby/1.8/timeout.rb:56:in timeout' from c:/ruby/lib/ruby/1.8/timeout.rb

How to reinstall a gem using bundler

I did a bundle show and get the complete path to a gem directory. Unfortunately, I removed the directory using rm -r gem_path . Then my rails app isn't working anymore. If I try start server or start rails console it outputs the following error: <class:Application> : uninitialized constant MyAPP::Application::Gem (NameError) What should I do to have it back? I tried bundle ins

如何使用捆绑器重新安装宝石

我做了一个bundle show并获得了一个gem目录的完整路径。 不幸的是,我使用rm -r gem_path删除了该目录。 然后我的导轨应用程序不再工作了。 如果我尝试启动服务器或启动rails控制台,则会输出以下错误: <class:Application> :未初始化的常量MyAPP::Application::Gem (NameError) 我应该怎么做才能恢复? 我尝试了bundle install或bundle update ,希望强制捆绑包搜索并重新安装,但是没有起作用。 我也尝